CSL gets orphan drug status for haemophilia-B treatment

CSL (ASX:CSL) subsidiary CSL Behring has been granted orphan drug designation from the US FDA for a treatment for haemophilia-B

The company has been awarded the designation for its recombinant fusion protein linking coagulation factor IX with recombinant albumin, rIX-FP.

The designation covers the treatment, control and prevention of bleeding episodes in haemophilia-B patients.

Factor IX is a blood coagulation protein. If factor IX proteins are deficient or defective, it can result in the onset of haemophilia-B

Haemophilia-B is less common than haemophilia-A, affecting an estimated one in 25,000 to 50,000 people. This compares to around one in 5,000 to 10,000 people for haemophilia-A – which is caused by deficiencies in coagulation factor VIII.

The standard treatment for haemophilia-B is factor IX replacement therapy, but some patients develop inhibitory antibodies which reduce the effectiveness of the treatment. In these cases, one option is to use a recombinant protein, or a bypassing agent.

CSL Behring's rIX-FP, which is being developed in conjunction with its parent company, is designed to extend the half-life of factor IX by fusion with recombinant albumin.

The company revealed it had selected albumin due to its long physiological half-life, low potential for allergic reaction and tolerability profile.

CSL Behring VP of research and development Val Romberg called the granting of the designation an “important regulatory milestone for our recombinant factor IX.”

CSL Behring is a US subsidiary of Melbourne-headquartered CSL, focused on the plasma protein biotherapeutics industry.

CSL (ASX:CSL) shares were trading 0.33% higher at $39.950.